For this assignment, a Naive Bayesian Classifier was constructed in Matlab, to
create a simple spam-filter. 

Most of the string-related methods were provided. One important modification had
to be made: The function \texttt{presentre} contained the following line:
\begin{lstlisting}
  N=size(RE,2);
\end{lstlisting}
which had to be changed to:
\begin{lstlisting}
  N=size(RE,1);
\end{lstlisting}
because the regular expressions have to be provided in a cell array, which does not have a second
dimension.
